Origin Use is Backwards? about jschannel

[l-cornelius-dol]

Making progress on this... it seems Firefox temporarily places an about:blank URL, which has the origin of the containing page, causing the attempt to ping the other window to fail if it happens too quickly, which it usually does. Unfortunately, there seems to be no reliable way to test which "window" is current in the frame. Might have to resort to try/catch silliness.

[l-cornelius-dol]

OK, so the problem was indeed the intermediate iframe in Firefox (did not test on other browsers). What I had to do was a little ugly:

setTimeout(function buildChannel() {                                                // frame (ifrwin) for channel not immediately available
    let chlscp="...my scope...";
    let chlorg=tskurl.match(/^[A-Za-z]{1,10}:\/\//)                                 // cope with either absolute or relative URL
               ? tskurl.split("/").slice(0,3).join("/")                             // reduce absolute URL to protocol://domain:port
               : window.location.origin;                                            // just use this window's domain for relative
    let ifrwin=ifrelm.contentWindow;
    try {                                                                           // will throw when real external URL becomes active, due to `""+ifrwin.location`
        if(!ifrwin || !ifrwin.location || ""+ifrwin.location=="about:blank") {      // about:blank needed for Firefox or will throw on bad origin
            setTimeout(buildChannel,20);                                            // frame not loaded, try again in a little bit
            return;
            }
        }
    console.log("Task collaboration channel is pending (scope="+chlscp+", origin="+chlorg+")");
    obj.channel=Channel.build({
        window  : ifrwin,
        ...

Will close this, but it would be useful for the library to cope with this situation.